Such an apparatus, which is also often called a vacuum lifter, is known. When an object sucked up on the suction gripper device is to be lifted off the ground, a control valve is moved in the closing direction, so that the clear cross-sectional area for the incoming air is less and the flow resistance thus is greater, so that with uniform suction performance of the vacuum-creating device, which can be a suction fan or the like, a bellows-like lifting hose contracts and lifts the suction gripper device together with the sucked-up object off the ground against the effect of weight. If the object is to be deposited again, the control valve is adjusted in the opening direction, so that the clear cross-sectional area increases again and more air can consequently flow into the interior of the suction gripper device or into the lifting hose, which causes the lifting hose to expand again because of the downward directed weight and the suction gripper device to be lowered with the sucked-up object.
European Patent 0493 979 A 1 discloses a suction gripper device with a surrounding oval handle, the control valve of which is formed by a swivelling flat flap which is attached to a U-shaped stirrup, which in turn is articulated in such a way that it can swivel about an axis running parallel to the plane of the handle. The U-shaped stirrup is operated by the fingertips of a hand gripping around the handle. If the stirrup is swivelled with the fingertips in the direction towards the handle, the valve flap is swung in front of a flow aperture, so that the effective flow cross-section of the latter is reduced. In order to be able to deposit a sucked-up body, the U-shaped stirrup must be pressed down fully, so that the swivelling valve flap fully clears the flow cross-section, which is constantly increasing in size in the opening direction. Operating errors often occur, for example when a user of the apparatus accidentally moves the stirrup too far downwards and the suction gripper device together with the sucked-up object is lowered very rapidly. A further disadvantage of the known apparatus is that the U-shaped swivelling stirrup is very easily shifted accidentally. If, for example, an object is being lifted and is to be held at a specific height for a short period, that can be set by means of the stirrup, but there is a risk of the stirrup being shifted when the handle is released, and of a lifting or lowering movement occurring.
European Patent 0590 554 A 1 discloses a further vacuum lifting apparatus which likewise has a swivelling valve flap arrangement, the valve flap preferably being movable under spring load into an initial position, in which it completely closes a first flow aperture, and opens a second, smaller flow aperture. In this position the level of the vacuum inside the suction gripper device or the lifting hose is set by a static valve which is, however, adjustable during operation and controls the flow cross-section of the second aperture. By setting this valve it is therefore possible to hold a lifted object at a desired height. The arrangement described is, however, expensive and has the disadvantages described above, in particular when the sucked-up object is being deposited.